Firing mechanism



June 17, 1941. w. SUMMERBELL- 2,245,623

FIRING MECHANISM Filed May 22, 1959 2 Sheets-Sheet 1 Fig.1.

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. FIRING MECHANISM Filed May 22, 1939 2 Sheets-Sheet 2 lTLVE 111: 1:11

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I Fl gs Patented June 17, 1941 FIRING MECHANISM William Summerbell,Watervliet, N. Y., assignor to Government of the United States ofAmerica, as represented by the Secretary of War and his successors inoifice Application May 22, 1939, Serial No. 274,987

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

The subject of this invention is a firing mechanism.

The purpose of the invention is to provide a firing mechanism in whichthe firing pin spring is rendered inoperable to enable the firing pin tocomplete its movement to firing position through its own inertia and tohave a corresponding unrestrained retraction to permit opening of atransversely movable breech block. This purpose is accomplished byproviding a heavy and a light spring acting through the intermediationof a member associated with a firing pin to drive the firing pin forwardand. then immediately retract it sufiiciently to clear a cartridge.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

Fig. 1 is a transverse sectional view of the improved firing mechanismwith the firing pin in the normal retracted position after being fired;

Fig. 2 is a similar view with the firing pin in cocked position;

Fig. 3 is a fragmentary longitudinal sectional view through the breechring with the upper part of the breech block in elevation;

Fig. 4 is a transverse sectional view of the firing pin guide;

Fig. 5 is a similar view of the stop collar in position to be insertedin the guide;

Fig. 6 is a view in front elevation of the guide with the stop collarassembled therewith.

Referring to the drawings by characters of reference there is shown abreech ring A having an opening for a vertically sliding breech block B,the mechanism for opening the block being omitted. The breech block isformed with a bore 6 which is closed at the face of the block by a plug1 having an aperture 8.

The firing mechanism which is housed in the bore 6 comprises a cap 9, astop collar i0, an outer spring ll, an inner spring l2 and a firing pinunit consisting of a guide l3 and a firing pin M.

The .guide I3 is a cylindrical member slidable in the bore 6 and havinga lug 15 on its left side movable in a slot It in the block and a camlug I! on its lower side movable in a slot IS in the block and servingto restrain the guide against rotational displacement. The front closedend I9 of the guide is centrallyapertured to threadedly receive thefiring pin I 4.

The opposite sides of the front end of the guide are cut away to thethickness of the end l9 to provide openings 20 for a pair'of forwardlyextending fingers 2l'2| formed on the stop collar l0 and arranged toengage the plug 1. The collar l0 provided with a central opening for thefiring pin, is slidably mounted within the guide l3 and adapted to bemoved into contact with the inner surface of the end l9 by the outerspring II.

The firing pin I4 extends rearwardly substantially the same distance asthe guide 13 and at its rear end it is formed With a head 22 for seatingthe inner spring l2. The front end of the spring I2 is seated on thecollar in adjacent the spring II.

The cap 9 which closes the bore 6 and confines the outer spring II isprovided on opposite sides with a pair of similar lugs 23-23 each havingits rear corners cut away as at 24 and each having, in its rear face, asemi-cylindrical recess 25,. A pin 26 fixed in the upper part of thebreech block depends into the bore 6 and serves to engage in the recess25 and hold the cap in place. The breech block is also formed with apair of spaced and opposite lugs 212l whose front faces are engaged bythe lugs 23 when the cap is inserted and given a partial turn. Inremoving the cap it is moved forwardly out of engagement with the pin 26and then it is turned until the lugs 23 are clear of the lugs 21.

The lug l5 extending laterally from the guide i3 is arranged to beengaged by the ofi'set lower arm 28 of a cocking lever 29, which ismounted on the breech block by means of a pivot pin 30. The upperextremity of the cocking lever extends above the breech ring and it iscurved so that, as it is lowered with the breech block, it may ride onthe breech ring and be rotated about its pivot to retract the firing pinunit to cocked position. A plunger 3| is provided to act on the lowerarm of the cocking lever and normally maintain the lower arm in theforward position.

During lowering of the breech block the cocking lever retracts the guideI3 to position shown in Fig. 2 thereby compressing the outer spring I lDuring this retraction the cam lug l'l moves the sear 32 laterallyagainst the action of a sear spring 33. When the lug l1 clears the searthe latter is restored by its spring to be interposed in the path of thelug l1 and in this manner the sear holds the firing mechanism in cockedposition. Since the trigger mechanism for tripping the sear forms nopart of the invention it is not shown or described.

When the firing mechanism is in the cocked position as seen in Fig. 2,the outer spring II is compressed and the collar I engages the end IQ ofthe guide 13. When the sear is disengaged the spring ll acts through thecollar to drive the guide l3 and the firing pin I4 forward. The fingers2| on engaging the plug '1 arrest the forward motion of the collar butthe firing pin, under the influence of inertia, continues forwardly tostrike the primer of a cartridge C. During this movement the firing pincompresses the inner spring l2. When the firing pin is arrested bystriking the primer, the inner spring I2 recovers and immediatelyretracts the firing pin point to a position within the plug I where itwill not interfere with opening of the breech block. The amount of thisretraction is limited by engagement of the end I9 with the collar I0.

I claim:

1. In a firing mechanism, a breech block having a bore, a hollow guideslidable within the bore and having an apertured front end, a firingpincarried by the front end of the guide and having a' rear portiondisposed within the guide, a collar slidable within the guide and havingfingers projecting forwardly through the front end of the guide toengage the breech block, a cap closing the bore of the breech block, aspring confined between the collar and the cap, and a spring confinedbetween the collar and the rear end of the firing pin.

2. In a firing mechanism, a breech block, a firing pin member slidablein the breech block, a collar engageable with the firing pin member,means for limiting forward movement of the collar short of the firingpin member, a spring seat member relatively fixed in the breech block, aspring confined between the collar and the Seat member, and a springconfined between the collar and the firing pin member.

3. In a firing mechanism, a breech block, a firing pin member slidablein the breech block, a collar engageable with the firing pin member,means for limiting forward movement of the collar short of the firingpin member, a spring seated on the breech block and acting on the collarto drive it forwardly, and a lighter spring seated on the collar andacting on the firing pin to move it rearwardly relative to the collar.

4. In a firing mechanism, a breech block, a firing pin member slidablein the breech block, a collar engageable with the firing pin member,means for limiting forward movement of the collar short of the firingpin member, means acting on the collar to drive it forwardly, and meansenergized by forward movement of the firing pin and acting from thecollar to move the firing pin member rearwardly relative to the collar.

WILLIAM SUMMERBELL.

